Rotation mechanism for rock drills



July 17, 1956 A. M. MosBY ROTATION MECHANISM FOR ROCK DRILLS 3 SheetsSheet 1 Filed Feb. 18. 1955 INVENTOR. Aauou: M. Mo sen s'fimpm v-AQa/yz'alzan AT To an EYS A. M. MOSBY 2,755,069 ROTATION MECHANISM FORROCK DRILLS July 17, 1956 3 Sheets-Sheet 2 Filed Feb. 18, 1955 mm IINVENTOR. Aauou: M. Mo sex 977Zmazq6mnm flm'awn.

ATTO RNEYS A. M. MOSBY ROTATION MECHANISM FOR ROCK DRILLS July 17, 19563 Sheets-Sheet 3 Filed Feb. 18, 1955 5 a Y E R u w 2 NM 0 E V T m m D LQ N R A mm 0. QM

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Uni ed ate 13mm I 2,755,069 p v ROTATION MECHANISM FoRiiocK DmLLs f 1Arnold M. Mosby, MidvalaN. J. I

Application February 18, 1955, Serial No. 489,070

Claims. (Cl. 25538) The present invention relates to rock drills of theflute actuated type and in particular to the rotation mechanisn for arock drill of that type.

The primary object of the present invention is to provide a rotationmechanismfor a rock drill which rotates the drill at the conventionalspeed with the piston traveling half the conventional distance.

Another object of the present invention is to provide a rotationmechanism for a rock drill which is sturdy, not subject to excessivewear and one which will stand long periods of usage as well as one inwhich the piston travel has been shortened permitting a lighterweight2,755,069 Pe eete wlv r 53*? Referring to Figures 1 to. 4, inclusive,the pneumatic hammer drill comprises a hollow cylinder :10, a reciprocalpiston 11, aro'tatable chuck 12, a rifle bar 13, and a rifle nut 14. Adrill steel 15 is held by the chuck-12 for striking by the end of thepiston 11.

The rifle bar 13 inwardly of one end thereof has'spiral flutes 16 whichare engaged by cooperating followers 17 carried by the rifle nut 14.

The other end of the rifle bar 13 has operatively con! nected thereto aratchet mechanism comprising dogs 18 carried by the enlarged end 19 ofthe rifle bar, the dogs being in engagement with notches or grooves cutin the inner periphery of a ratchet box 20 secured within one end of thecylinder 10. Springs 21 bias the dogs 18 into engagement with thegrooves of the ratchet box 20 preventing the rotation in one directionof the rifle bar 13.

Means is operatively connected to the piston for causing the piston inexecuting its reciprocatory movement in one direction to move by arotational sliding movement and in executing its reciprocatory movementin the opposite direction to move by a rotational sliding movement.

' Such means embodies spiral flutes formed on a portion of piston butkeeping the same speed of rotation of the drill.

These and other objects and advantages of the present invention will bemore fully apparent from the following description when taken inconnection with the annexed drawings, in which: r 1

Figure 1 is a side view in cross-section of a rock drill embodying theconstruction of the present invention,

Figure 2 is an end view in cross-section on line 2-2 of Figure 1,

Figure 3 is an end view in cross-section on line 3-3 of Figure 1,

Figure 4 is a view in perspective of the essential components of thepresent invention as applied to the rock drill of the type shown inFigure 1,

Figure 5 is a side view in cross-section of a further type of rockdrill, showingthe employment of the construction of the presentinvention,

Figure 6 is an end view in cross-section on line 6-6 of Figure 5, a p

Figure 7 is a further end view in cross-section on line 7-7 of Figure 5,

Figure 8 is a view in perspective of the essential components of thesecond type of rock drill using the construction of the presentinvention, v i

Figure 9 is a view in cross-section of a rockdrill constructed accordingto the present invention, v

Figure 10 is an end view in cross-section on line 10--10 Figure 11 is afurther end view in cross-section on line 1111 of Figure 9, and

Figure 12 is a view in perspective of the components of the presentinvention as used in a rock drill constructed according to the presentinvention.

In the rock or pneumatic hammer drills, as heretofore proposed, therifle bar and rifle nut have spiral flutes and cooperating followers,respectively, enabling the piston to rotate on one of its strokes,usually the upstroke or return stroke.

,of the drill to turn within the hole being drilled.

the piston 11 and a nut 24 having on its inner periphery cooperatingfollowers engageable in said flutes, the flutes being pitched in theopposite direction to thatof the flutes on the rifle bar. 1

In the form of the invention shown in Figures 1 to 4; inclusive, suchmeans constitutes flutes 22 on the striking end of the piston 11 and inwhich ride the followers 23 formed on the inner periphery of the nut 24.V a

The nut 24 is provided on its outer periphery with spiral splines 25which are pitched to the same direction, and to approximately the samedegree, as are the spiral flutes 22 on the piston 11. The said spiralsplines 25 engage grooves cut in the inner periphery of the end of thechuck 12 for connecting the piston 11 to the chuck 12.

The pitch of the flutes 16 and 22 on therifle bar 13 and on the piston11 respectively may be such as to cause one revolution of the chuck inevery 20, 30, or 40 reciprocatory movements of the piston. v

In the operation of this pneumatic hammer drill, the rifle bar 13 isheld by the ratchet mechanism for rotation in only one direction. Uponthe downstroke or striking stroke of the piston 11, the flutes 16 on therifle bar 13 and the followers 17 upon the rifle nut 14 impart a rotarymotion to the rifle bar 13, the inertia and weight of the rifle bar 13being less than that of the piston. Upon the upstroke or return strokeof the piston 11, the rifle bar is held from rotation and the followers17'riding in the flutes 16 impart a rotary motion to the piston 11 inthe direction of the arrow, as shown in Figure 1.

During the upstroke or return stroke of the piston 11, the flutes 22 onthe piston and the followers 23 on the nut 24 cause the nut 24 and theconnected chuck 12 to rotate in the same direction as the piston but fortwice the distance of rotation of the piston.

On the down stroke or striking stroke, the piston will turn so that theflutes 22 slide between the followers 23, the weight of the piston 11being less than the weight of the chuck 12 with the attached drillsteel.

The pitch of the flutes 16 and 22 may be the same and may be at such anangle with respect to the longitudinal axis of the rifle bar 13 and thepiston 11 that the impact of the respective flutes and followers benegligible and the resultant rotation of the drill steel be the same asin rock drills heretofore proposed in which only the rifle bar and therifle nut had spiral flutes and followers, respectively. To obtain the.same degree or speed of rotation in the rock drill heretofore proposed,the pitch of the flutes would be much greater than that employed in thepresent invention.

In the form of the rock drill shown in Figures 5 to 8, inclusive, therifle bar and the rifle nut are omitted and the piston 25 is provided ona portion inwardly of one end with opposed pairs of flutes 26 and 27which are disposed in spiral arrangement upon such portion of the piston25 with the flutes of one pair being pitched in a direction opposite tothe pitch of the flutes of the other pair.

A nut 28 provided with cooperating followers 29 slides upon the strikingend of the piston 25 with the followers 29 engaged in the pair of pistonupstroke flutes 27.

A sleeve 30 is secured to the impeller nut 28 and is provided on itsouter periphery with grooves or notches 31 which are engaged by the dogs32 carried in the wall of the cylinder 33 and permit the rotation of thenut 28 in only one direction.

.A chuck nut 34 is provided with cooperating followers 35 which engagethe other pair of flutes 26 on the piston 25. The outer periphery of thenut 34 is provided with spiral splines 36 which fit within the sprialgrooves formed on the inner wall of the chuck 37 and secure the chucknut 34 to the chuck 37 for rotational move ment of the latter uponreciprocal motion of the piston 25 during its upstroke when the nut isheld from rotation by the dogs 32.

The operation of this form of the invention is similar to that of theform shown in Figures 1 to 4, inclusive. The pair of flutes 27 and thecooperating followers 29 on the nut 28 cause the piston to rotatecounterclockwise upon its upstroke and effect the furthercounterclockwise rotation of the chuck 37 for twice the distance ofrotation of the piston 25.

But in addition, the piston 25 can effect the same speed of standardcounterclockwise rotation on its downstroke, when desired, as is moreusually effected upon its upstroke. To perform downstroke rotation, thecooperating followers 29 on the nut 28 are pitched to engage the pair offlutes 26 on the piston 25, and the co operating followers 35 of the nut34 are pitched to engage the pair of flutes 27 on the piston 25.

On the downstroke, the lighter weight and less inertia of the nut 28with respect to the weight and inertia of the piston 25 causes the nut28 to rotate, the piston also rotating because it is lighter in weightand has less inertia than the chuck and the attached drill steel. Thisrotation on the down stroke is not positive with respect to the pistonand little impact on the flutes and associated followers results. Itwill be seen that because of the pitch of the flutes 26 and 27 being thesame, the chuck is caused to rotate twice as far as the piston.

In the third form of the invention, the rifle nut and the rifle bar areagain omitted and the cylinder 38 has slidable within it a piston 39having on a portion inwardly of one end flutes 40 and 41 disposed in endto end relation with respect to each other.

The flutes 40 and 41 have identical pitches but are arranged upon thepiston 39 in opposite directions. The nut is formed from two halves 42and 43, each half being provided with the followers 44 which engage andride in the flutes 40 on the piston 39. A nut 45 has followers 46 whichride in the flutes 41. A transistor sleeve 47 is disposed between thenut and the nut and is dimensioned in length equal to the greatestlength of stroke of the piston 39 so that the nut and the nut slide upontheir respective portions of the piston 39.

The nut is provided with a ratchet sleeve 48 having its outer peripheryformed with grooves or notches 49 which are engaged by the dogs 50 whichprevent the ratchet sleeve 48 from rotating in one direction. Springs 51carried in the cylinder 38 bias the dogs 50 into engagement with thenotches in the ratchet sleeve 48.

The nut 45 is provided with spiral splines 52 on its outer periphery,pitched to the same direction, arfd the same degree, as the spiralflutes *41 on the piston 39,

4 the spiral splines 52 engaging the internal spiral splines in thechuck 53 to secure the nut. The spiral splines 52 are pitched to thesame left-hand direction whether the counterclockwise rotation of thechuck 53 is to be effected by the upstroke of the piston or by thespecialpurpose downstroke of the piston.

The operation of this form of the invention is the same as that of theforms previously described. Upon the return or upstroke of the piston39, the dogs engaging the grooves or notches 49 in the ratchet sleeve 48prevent the nut from turning and cause the piston 39 to rotate in thedirection shown by the arrow in Figure 9.

The nut with its associated followers riding in the flutes on the piston39 cause the chuck to rotate in the direction indicated by the arrows inFigure 9 also, and for twice the distance of rotation of the piston.

In each of the three forms of the invention here described, the rotationof the chuck is twice that of the piston. In most industrialapplications of the rock drill or pneumatic hammer drill, cooperatingflutes of the chuck nut and the rifle bar are pitched at one of threestandard degrees of pitch so that the speed of rotation of the drill isat one revolution for every 20, 30, or 40 reciprocating strokes of thepiston. It is seen therefore that when the chuck rotates at twice thespeed of the piston, the stroke of the piston may be cut to half orapproximately half to obtain the same speed of rotation of the chuck andits attached drill steel with a shorter stroke of piston. The Weight ofthe piston may be considerably less and higher speeds of operation arethereby permitted.

The present invention also permits the pitch of the flutes to be less oneach of the components having the flutes in order to obtain the samespeed of rotation of the drill steel. When the piston or the rifle baris formed with flutes having the minimum pitch, there is less wear anddamage to the flutes and their respective followers by the impact of thepiston in each direction of reciprocatory motion.

By the means so described, in all three forms of this invention, the nutis so secured within the chuck that the reciprocating movement of thepiston, which with upstroke rotation tends to extract the chuck nut fromthe chuck, is exactly countered and effectively neutralized. Noadjustment of pitch to downstroke rotation is necessary. The chuck nutwill not become impacted, or riveted, into the chuck and thereby be madeextremely difficult to extract from the chuck when worn, as heretoforehas been the problem resulting from the use of threaded chuck nuts andchucks.

In all three forms of this invention, the extractive pull of the pistonagainst the chuck nut is reduced in proportion to the reduction in pitchof the related functioning rotation flutes and followers. By pitchingthe nut-securing splines equally with 20-stroke rotation splines on thestriking end of the piston, or for the fastest speed of. chuck rotation,the nut is secure at any other slower rotation speed.

What is claimed is:

1. In a pneumatic hammer drill, a hollow cylinder, a piston mounted insaid cylinder for reciprocatory movement, means operatively connected tosaid piston for causing said piston in executing its reciprocatorymovement in one direction to move by a rotational sliding movement andin executing its reciprocatory movement in the opposite direction tomove by rotational sliding movement, said means embodying spiral flutesand a nut having on its inner periphery cooperating followers engageablewith said flutes, a drill carrying chuck, and means connecting saidchuck to said piston so that said chuck rotates when said piston isexecuting its reciprocatory movement in said opposite direction, saidlast named means embodying spiral flutes formed on said piston andpitched in a direction opposite to that of the pitch of said flutes ofsaid first named means, a nut having on its inner periphery cooperatingfollowers engageable with and riding back and forth in said flutes ofsaid second named means, and interengaging means on the outer peripheryof said second named nut and on said chuck.

2. In a pneumatic hammer drill, a hollow cylinder, a piston mounted insaid cylinder for reciprocatory movement, means operatively connected tosaid piston for causing said piston in executing its reciprocatorymovement in one direction to move by a rotational sliding movement andin executing its reciprocatory movement in the opposite direction tomove by rotational sliding movement, said means embodying a rifle barhaving spiral flutes formed thereon and a nut having on its innerperiphery cooperating followers engageable with said flutes, a drillcarrying chuck, and means connecting said chuck to said piston so thatsaid chuck rotates when said piston is executing its reciprocatorymovement in said opposite direction, said last named means embodyingspiral flutes formed on said piston and pitched in a direction oppositeto that of the pitch of said flutes of said first named means, a nuthaving on its inner periphery cooperating followers engageable with andriding back and forth in said flutes of said second named means, andinterengaging means on the outer periphery of said second named nut andon said chuck.

3. In a pneumatic drill, a hollow cylinder, a piston mounted in saidcylinder for reciprocatory movement, spiral flutes extendinglongitudinally along a portion of said piston, a nut having on its innerperiphery cooperating followers engageable with said flutes, said nutbeing operatively connected to said cylinder for rotational movement ofsaid nut in one direction in response to rectilinear sliding movement ofsaid piston in one direction and operatively connected to said pistonfor causing rotational movement of said piston upon execution of slidingmovement of the latter in the opposite direction, other spiral flutesextending longitudinally along another portion of said piston, the firstnamed flutes being pitched in a direction opposite to that of the pitchof said other flutes, a drill carrying chuck mounted in said cylinderfor rotational movement, and another nut having on its inner peripheryother cooperating followers engageable with said other flutes, saidanother nut being operatively connected to said chuck for rotationalmovement of said chuck in the same direction as said piston uponexecution of sliding movement of said piston in said opposite direction.

4. In a pneumatic drill, a hollow cylinder, a piston mounted in saidcylinder for reciproeatory movement, spiral flutes extendinglongitudinally along a portion of said piston, a nut having on its innerperiphery cooperating followers engageable with said flutes, said nutbeing operatively connected to said cylinder for rotational movement ofsaid nut in one direction in response to rectilinear sliding movement ofsaid piston in one direction and operatively connected to said pistonfor causing rotational movement of said piston upon execution of saidsliding movement of the latter in the opposite direction, other spiralflutes extending along said portion of said piston in the oppositedirection to said first named flutes, the first named flutes beingpitched in a direction opposite to that of the pitch of said otherflutes, a drill carrying chuck mounted in said cylinder for rotationalmovement, and another nut having on its inner periphery othercooperating followers engageable with said other flutes, said anothernut being operatively connected to said chuck for rotational movement ofsaid chuck in the same direction as said piston upon execution of thesliding movement of said piston in the opposite direction.

5. In the pneumatic drill, a hollow cylinder, a piston mounted in saidcylinder for reciprocatory movement, spiral flutes extendinglongitudinally along a portion of said piston, a nut having on its innerperiphery cooperating followers engageable with said flutes, said nutbeing operatively connected with said cylinder for rotational movementof said nut in one direction in response to rectilinear sliding movementof said piston in one direction and operatively connected to said pistonfor causing rotational movement of said piston upon execution of thesliding movement of the latter in the opposite direction, other spiralflutes extending in end to end relation with respect to said first namedflutes along another portion of said piston in the opposite directionand at the same angle as said first named flutes, the first named flutesbeing pitched in a direction opposite to that of the pitch of said otherflutes, a drill carrying chuck mounted in said cylinder for rotationalmovement, and another nut having on its inner periphery othercooperating followers engageable with said flutes, said another nutbeing operatively connected to said chuck for rotational movement ofsaid chuck in the same direction upon execution of the sliding movementof said piston in said opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS1,522,336 Slater Jan. 6, 1925 2,169,637 Gartin Aug. 15, 1939 2,688,268Lear Sept. 7, 1954

